Jordin Sparks and her shapely body cover the May issue of Women's Running magazine. The sexy singer flaunts her 50-pound weight loss on the cover, striking a runner's pose and a stunning smile. Could she be any more gorgeous? No! She also revealed some of her size-dropping secrets, and how her boyfriend, fellow pop singer Jason Derulo, factored into it.

"I put my iPod on shuffle," the singer said about what she listens to while exercising. "If it's a slow song, I turn the incline way up and jog to the beat. If a faster song comes on, I turn the incline down and watch the miles fly by."

Who are her faves to fill her ears via her headphones or earbuds? "Kanye West, Jay-Z and I listen to Jason a lot," Sparks said. About the latter, she admitted, "I can't help that -- it's just nice to hear his voice." That certainly helped motivate her and she ended up dropping four dress sizes.

But it's not just her man's music that inspires her. As if! She inspires herself. "I've also been listening to some new uptempo stuff of my own that I'm excited for people to hear," the former 'American Idol' winner said.

Don't go misconstruing what Sparks said about her BF motivating her to get in shape. Our loved ones are the people who motivate and support us and that's just what Jason Derulo seems to be doing, be it through his voice or otherwise.